GB637185A - Improvements in the production of pre-stressed reinforced concrete sleepers and similar beams - Google Patents

Abstract

Moulds for concrete sleepers or similar beams, which may have slotted removable end plates, as described in Specification 572,387, are successively assembled around reinforcing wires stretched above each of one or more production lines, which may be low brick or concrete walls, and slid along the lines either on a track, e.g., a roller track, or on the reinforcing wires until the lines are full. As each mould arrives at its position it is supported if necessary on wedges or adjustable feet. After tensioning the wires the moulds are filled with concrete from a hopper or bucket carried by an overhead travelling crane having a transverse bridge which extends across all the lines. During and/or after filling each mould is vibrated by an electrical or mechanical vibrator manually applied to the mould. After hardening, which may be accelerated by the process described in Specification 602,024, the wires between the moulds are cut and the crane used to remove the sleepers, with or without the moulds. The last mould is then hauled along each line to stretch new lengths of wires above the lines, the wires running off reels on vertical shafts at one end of the production lines. When the moulds are slid along the wires the end plates have to be closed before moving the moulds and the moulds and end plates may have wheels, hooks or the like to engage the wires and facilitate the movement. Specifications 572,385 and 572,390 also are referred to.